1. Field of the Invention
This invention relates generally to computer systems, and more particularly to methods and associated systems for transferring data between storage systems.
2. Description of the Background Art
For back-up purposes, data stored in a disk unit of a local mainframe computer system are copied to a remote storage device to prevent data loss in the event of a disaster such as a disk crash or facility shutdown. U.S. Pat. No. 6,098,129 to Fukuzawa et al. (“Fukuzawa”) discloses a configuration for backing-up data from a mainframe computer system (“mainframe”) to an open computer system. Although Fukuzawa discloses the use of low-cost open computer system storage devices for backing-up mainframe data, Fukuzawa does not disclose the use of another mainframe storage device for back-up.
Because mainframes are generally more reliable than other types of computer systems, data stored in the disk unit of a mainframe are ideally backed-up to a disk unit of another mainframe. Remote dual copy functions, which involve the backing-up of stored data from one computer system to another in real-time, have been performed between mainframes using the so-called Count-Key-Data (“CKD”) protocol. The CKD protocol allows currently available mainframes to transfer data at a rate of approximately 17 MB/s (mega-bytes/second). To increase the amount of data that can be copied from one mainframe to another within a period of time, it is desirable to obtain a data transfer rate that is faster than what is currently obtainable using the CKD protocol.